1. Field of the Invention
This invention is directed to coating compositions, in particular, to coating composition useful as interior and exterior top coats, base coats, primers, primer surfacers and primer fillers having excellent physical properties, such as, flexibility, hardness, chip resistance and when used as a primer, a primer surfacer or a primer filler also has a combination of excellent sandability and chip resistance.
2. Description of the Prior Art
Finishes used in the manufacture, repair and refinish of automobile and truck bodies and parts, industrial equipment, appliances and the like must provide a high quality appearance and have excellent physical properties to withstand long term use, particularly when exposed to weathering. Many finishes now in use are multi-layered finishes and each layer has different requirements. For example, the multi-layer finishes on automobile and truck bodies and parts typically utilize the following: (1) an electrocoat layer applied over a substrate, typically, a phosphatized cold rolled steel, (2) a primer layer, (3) a colored layer, typically pigmented, and (4) a clear layer. A colored top coat layer may be used in place of the colored layer and clear layer. On repairing or refinishing such multi-layer finishes, a suitable primer, primer surfacer or primer filler coating is applied over the multi-layer finish that usually is sanded thereby exposing one or more layers or is applied over a filler material that has been used to fill in surface imperfections.
This primer, primer surfacer or primer filler, herein after, “primer”, has many requirements. It must have adhesion to the substrate and provide a surface to which the colored layer or top coat will adhere. It must be readily sandable in a reasonably short period of time after application, for example, about three hours after application. It must provide the resulting multi-layer finish with good impact resistance, in particular, stone chip resistance.
Coatings used to form finishes on appliances, flexible and rigid thermoset or thermoplastic substrates, industrial equipment, exterior structures, and the like may be applied directly to the substrate which may be untreated, primed or surface treated. The resulting finish must have the required properties for its intended use.
It would be desirable to have a basic coating composition that can be formulated to meet the physical demands of these wide varieties of end uses. The novel composition of this invention can be readily formulated using conventional techniques to form finishes that have the required physical properties that meet typical end use requirements for the above applications. Also, it would be desirable that such a composition contains components that are derived from renewable resources. The novel composition of this invention meets these aforementioned requirements.